DK2841178T3

DK2841178T3 - Device for clearing a supernatant received in a clearing pool.

Info

Publication number: DK2841178T3
Application number: DK13715909.1T
Authority: DK
Inventors: Marcus Höfken
Original assignee: Invent Umwelt- Und Verfahrenstechnik Ag
Priority date: 2012-04-27
Filing date: 2013-03-20
Publication date: 2016-08-15
Also published as: KR102070454B1; EP2841178B1; CN104302373B; IL235314B; PL2841178T3; BR112014026647B1; JP6251727B2; US9586161B2; DE102012207146A1; DE102012207146B4; CA2871709A1; HUE030075T2; TW201406440A; CA2871709C; KR20150006832A; WO2013160030A1; MX355383B; US20150114892A1; EP2841178A1; ES2584828T3

Description

The invention relates to a device for decanting a supernatant received in a clarifier. WO 2008/014856 and DE 10 2006 036 591 A1, respectively, concern a device for decanting a supernatant received in a clarifier, comprising: a decanter which is pivotally attached to a clarifier and which comprises a pipe, of which one end is held pivotally in a pivot bearing and at the other end of which a decanter head extending perpendicularly thereto and having a water inlet opening is provided, a pivoting device which is connected to the decanter via an actuator with an adjustable length for raising and lowering the water inlet opening relative to a floor of the clarifier.

According to the prior art, it is also generally known to attach a hydrostatic sensor to the decanter head. The hydrostatic sensor is connected via a cable to a controller provided outside the clarifier. A motor for driving the cable winch in accordance with the signals delivered from the hydrostatic sensor is controlled by means of the controller, such that an immersion depth of a water inlet opening provided on the decanter head is kept in a predefined range.

In practice, the hydrostatic sensor sometimes fails or the cable provided between the hydrostatic sensor and the controller is sometimes damaged. In the case of damage to the cable, this may also result in damage to the controller. EP 0 128 122 A1 discloses a decanter head, which is attached to one end of a pipe. The pipe is pivotally supported at the other end. The decanter head is at tached to a vertically adjustable rod and is, therefore, adjustable in height. US 4,158,678 A discloses a decanter head which is liftable by a cable pull. EP 0 979 668 A2 concerns a decanter head, which is attached at one end of a pipe. The pipe is pivotally supported at the other end. The decanter head is ad justable in height by a linear drive. WO 95/23638 A1 discloses an overflow edge controlled by a linear drive. DE 70 38 786 U concerns a decanter head, which is attached to one end of a pipe. The other end of the pipe is pivotally supported. The decanter head is adjustable in height by a chain. DE 86 23 253 U1 concerns a decanter head attached to a vertical device which is movable in a guiding assembly. The device can be moved vertically by a cable pull. US 4,693,821 A discloses a decanter head, which is attached to one end of a pipe. The pipe is pivotally supported at its other end. The decanter head is adjustable in height by a linear drive.

The object of the invention is to overcome the disadvantages according to the prior art. In particular, a device for decanting a supernatant received in a clarifier is to be specified, which device is not susceptible to faults and is robust. In accordance with a further objective of the invention, it is to be possible to produce the device with simplified complexity of manufacture.

This object is achieved by the features of Claim 1. Expedient embodiments of the invention will emerge from the features of Claims 2 to 8.

In accordance with the invention, the generic device for decanting a supernatant received in a clarifier comprises the following features: a first measuring device for measuring a fill level of the wastewater received in the clarifier, a device for determining a length of the actuator, an evaluating device with which a distance of the water inlet opening of the decanter to the floor of the clarifier can be determined from the length of the actuator, and a controller for controlling the pivoting device such that a water inlet opening immersion depth, which results from the difference between the fill level and the distance, is kept in a specified range.

In contrast from the prior art, it is possible with the proposed device to dispense with the provision of a hydrostatic sensor on the decanter head. Consequently, a susceptibility to faults or repair of conventional devices caused as a result of said sensor can be avoided. The proposed device according to the invention is of sim- pie structure, robust and is not susceptible to faults. With the device according to the invention, all parameters necessary for determining the immersion depth can be measured by means of measuring devices, which are fitted outside the wastewater received in the clarifier. There is no need for an undesirable laying of cables through the wastewater received in the clarifier. The proposed device is characterised by a lower complexity of manufacture and assembly.

The actuator with adjustable length may be a hydraulically adjustable pipe, an actuator adjustable for example by means of a spindle drive or the like, etc. In accordance with a particular advantageous embodiment, the actuator is selected from the following group: cable, belt, chain. In this case, the pivoting device comprises a winch for receiving such an actuator. To drive the winch, an electric motor or a hydraulic motor can be provided. The proposed actuator and also the proposed pivoting device are robust and are not susceptible to faults and are additionally available relatively cost-efficiently.

In particular with use of a belt, a first width of the winch may correspond approximately to a second width of the belt, such that the belt is received on the winch substantially congruently. The use of a belt and a winch corresponding thereto enables a reproducible winding and unwinding. The immersion depth of the water inlet opening can thus be controlled particularly precisely.

In accordance with a further embodiment, the device for determining the length of the actuator comprises a second measuring device for measuring an angle of rotation of the winch. Such a measuring device is conventionally available. For example, said measuring device may be provided on a motor, a gearing provided downstream of the motor where applicable, or on the winch itself. The second measuring device for example comprises a perforated or slitted disc and an optical detector, with which, in the case of a rotation of the perforation or slitted disc, an angle of rotation can be determined from the determined number of holes or slits. Other suitable measuring devices for example comprise a disc with magnetic markings and a detector or the like corresponding thereto. The use of motion sensors, for example gyro sensors or the like, is also conceivable.

The respective length of the actuator can be determined from the measurement of the angle of rotation. The angle of rotation and the length of the actuator determined from said angle again correspond to the distance. In the case of the use for example of a belt and a winch, there is no linear relationship between the an- gie of rotation and the length of the actuator or the distance. In this case, a corresponding correction function is stored in the evaluating device, with which correction function the respective distance can be determined from the measured angle of rotation. Such a correction function can be fixedly defined. However, said correction function may also be calculated on-site by measuring a maximum and a minimum pivot position of the decanter and can be stored in the evaluating device. It is thus possible in a particularly simple manner to adapt the controller to the respective conditions. The evaluating device may comprise a control stage with which the immersion depth can be controlled.

In accordance with a further embodiment, the controller comprises a first switching function, with which an operation of the pivoting device is interrupted when a predefined upper position of the decanter head is reached. Further, the controller may comprise a second switching function, with which an operation of the pivoting device is interrupted when a predefined lower position of the decanter head is reached. The switching functions can be programmable, for example. However, suitable switching elements for detecting the upper and the lower position of the decanter head can also be provided. With the proposed switching functions, a pivot operation outside a predefined pivot range of the decanter is avoided securely and reliably. This contributes further to the lack of susceptibility to faults of the device.

An embodiment of the invention will be explained in greater detail on the basis of the drawings, in which:

Fig. 1 shows a plan view of a device according to the invention,

Fig. 2 shows a sectional view according to the line of section A-A in Fig. 1,

Fig. 3 schematically shows a block diagram of a controller,

Fig. 4 schematically shows the length of the actuator over the number of revolutions of the winch, and

Fig. 5 schematically shows the distance over the number of revolutions of the winch.

In Fig. 1 and 2 a decanter 2 is held pivotally at one end thereof on a pivot bearing 3 in a clarifier 1. The decanter 2 has a pipe 4 extending from the pivot bearing 3 and a decanter head 5 arranged at the second end of the pipe 4 and extending perpendicularly thereto. The decanter head 5, on the underside thereof facing a floor B of the clarifier 1, has a lit-shaped water inlet opening 6. Reference sign 7 denotes a winch, on which a cable 8 connected to the decanter head 5 is received. Reference sign L denotes a length of the actuator or of the cable 8. The length L describes the respective distance between the decanter head 5 and the pivoting device or the winch 7.

Reference sign 9 denotes a first measuring device for measuring the fill level H1 of wastewater Ab received in the clarifier 1. The first measuring device may be an ultrasound or radar measuring device. A distance between the water inlet opening 6 and the floor B is denoted by reference sign H2. The immersion depth E of the water inlet opening 6 denoted by reference sign E is given from the difference between the fill height H1 and the distance H2. The immersion depth is expediently kept, in practice, in a range from 30 to 80 cm, preferably from 40 to 70 cm.

Fig. 3 schematically shows a block diagram of a controller S. The controller S may be a conventional process computer controller. Reference sign 10 denotes a second measuring arrangement, with which an angle of rotation of the winch 7 is measured and transmitted to the controller S. The fill height H1 is measured with the first measuring device 9 and a corresponding signal is also transmitted to the controller S.

By means of the controller S, the distance H2 is determined from the angle of rotation measured by the second measuring device 10. Further, a difference between the fill level H1 and the distance H2 is calculated with the controller S. An immersion depth E given therefrom is compared with a predefined value of the immersion depth E. In accordance with the result attained with the comparison, the motor M provided to drive the winch 7 is actuated such that the immersion depth E is set to the predefined value of the immersion depth E.

Fig. 4 schematically shows the unwound length L of the cable 8 or of the actuator over the number of revolutions U of the winch 7. With decreasing number of revolutions U of the winch 7, the diameter thereof increases due to the cable 8 wound thereon. The length L of the cable 8 decreases per revolution U of the winch 7 with increasing number of revolutions U.

Fig. 5 schematically shows the distance H2 over the length L of the actuator 8. The distance H2 and the length L of the actuator have a trigonometric relationship with one another.

With use of the functions shown in Fig. 4 and 5, the distance H2 can be determined from the respective angle of rotation of the winch 7. In Fig. 4 and 5, the respective angle of rotation is given by multiplying the number of revolutions of the winch 7 by 360°.

List of reference signs 1 clarifier 2 decanter 3 pivot bearing 4 pipe 5 decanter head 6 water inlet opening 7 winch 8 cable 9 first measuring device 10 second measuring device

Ab wastewater B floor E immersion depth H1 fill level H2 distance L length M motor S controller

Claims

A device for decanting a supernatant received in a clearance pool (1), comprising: A decanter (2) pivotally attached to a clearance pool (1) and comprising a tube (4), one end of which is held rotatable in a tab bearing (3) and at the other end of which is located a decanter head (5) extending perpendicular thereto and comprising a water inlet opening (6), a pivot device (7) connected to the decanter (2) via an adjustable length actuator (8) for raising and lowering the water inlet opening (6) relative to a floor (B) in the clearing basin (1), a first measuring device (9) for measuring a waste water level (H1) ( Ab) received in the clearing basin (1), an apparatus for determining a length (L) of the actuator (8), an evaluation apparatus with which a distance (H2) between the water inlet opening (6) of the decanter (2) and the clearing basin (1) floor (B) via a trigonometric relationship can be determined from the length (L) of the actuator (8) and a control unit (S) for controlling the turning device (7) such that a depression depth (E) of the water inlet opening (6) resulting from the difference between the filling level (H1) measured by the measuring device (9) and the distance (H2) determined by the evaluation device can be kept at a specified range.

Device according to claim 1, wherein the actuator (8) is selected from the following group: cable, belt, chain, and wherein the turning device comprises a winch (7) for receiving such an actuator (8).

Device according to claim 1 or claim 2, wherein an electric motor (M) or a hydraulic motor for driving the wind (7) is provided.

Device according to any one of the preceding claims, wherein, using a belt, a first width of the wind (7) corresponds approximately to a second width of the belt, so that the belt is received substantially congruently on the wind (7). .

Device according to any one of the preceding claims, wherein the apparatus for determining the length (L) of the actuator (8) comprises a measuring device (10) for measuring the angle of rotation of the wind (7).

Apparatus according to any one of the preceding claims, wherein the evaluation apparatus comprises a control step by which the immersion depth (E) can be controlled.

Device according to any one of the preceding claims, wherein the control (S) comprises a first coupling function by which the operation of the rotating device (7) is interrupted when a predetermined upper position of the decanter head (5) is reached.

Device according to any one of the preceding claims, wherein the control (S) comprises another coupling function, by means of which the operation of the rotating device (7) is interrupted when a predetermined lower position of the decanter head (5) is reached.